(a) Field of the Invention
The present invention relates to a method and a system of heating a cabin of a hybrid electric vehicle. More particularly, the present invention relates to a method and a system of heating a cabin of a hybrid electric vehicle that minimizes operation of a heater and an engine by lowering demand temperature of coolant taking into account power of the heater and improves fuel economy accordingly.
(b) Description of the Related Art
Generally, a hybrid electric vehicle (HEV) uses an engine and a motor as power sources. The hybrid electric vehicle enhances fuel economy by providing an electric vehicle (EV) mode when the engine is stopped and the vehicle is driven only by the motor. The hybrid electric vehicle, different from a typical vehicle using fossil fuel such as gasoline or diesel, selectively operates the engine. The engine of a typical vehicle generates power to drive the vehicle as well as power for driving an air conditioner of the vehicle. Particularly, coolant warmed up by the engine to heat a cabin of the vehicle (e.g., the interior of the vehicle) exchanges heat with the air while passing through a heat exchanger disposed near the cabin, and the heated air through heat-exchange with the coolant is supplied into the cabin to heat the interior of the vehicle.
However, since the engine is not always operated in the hybrid electric vehicle, an additional heater for heating the cabin is required. In other words, the air heated through heat-exchange with the coolant is supplied to the cabin of the vehicle during a heating mode of the hybrid electric vehicle, but the heater is operated and heats the air supplied to the cabin of the vehicle when coolant temperature is substantially low. Operation of the heater is controlled only by the coolant temperature according to a conventional hybrid electric vehicle. That is, when the coolant temperature is lower than predetermined temperature, the heater is operated. Therefore, power consumption of the heater increases. When the power consumption of the heater is above a threshold and state of charge (SOC) of a battery is substantially low, the engine is operated to charge the battery. Therefore, fuel consumption may be deteriorated.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.